Eureka!

Into the Drink

Building the ultimate solar-powered water purifier

Perhaps you’ve seen celebrity adventurist Bear Grylls
transform foul liquids into drinkable water using little more than
sunlight and plastic sheeting. Now, a UB-led interdisciplinary team
of researchers has turned this rudimentary survival tactic into a
highly productive yet still inexpensive method to make contaminated
water, or even saltwater, potable. The advancement could help to
address drinking water shortages in developing or disaster-stricken
regions.

Called a solar still, this type of contraption is nothing new,
but current models tend to be inefficient and costly to build. With
its innovative addition of a carbon-dipped paper surface that both
soaks up and heats up liquid, this one can produce 3 to 10 liters
of water a day. That’s up to three times the output of
commercial solar stills of similar proportions (about the size of a
mini-fridge). Because the new design forgoes pricey optical
concentrators, like mirrors and lenses, it costs dramatically less
to make.

Illustration by Robert Wilder, BFA ’02

Here’s how it works:

A: A layer of porous paper absorbs water like a napkin,
while its black carbon coating attracts and absorbs solar energy to
vaporize the water. A layer of polystyrene foam underneath the
paper provides insulation and buoyancy.

B: A clear, lightweight structure traps the water vapor
as it rises, then cools and condenses.

C: A separate chamber collects the distilled liquid, now
free of salt and contaminants. Cheers!

Qiaoqiang Gan

Qiaoqiang Gan, associate professor of electrical engineering in
UB’s School of Engineering and Applied Sciences, was lead
researcher on the project.